NWEA does not recommend a cut-point for entry into any specific tier of remediation. That, in most cases, is a district or school’s decision. The purpose of a screener is to identify which students are most likely to need intervention, not to determine the level of intervention.

Should I assign students directly to tier 3 based on their RIT score?

A screener is not the tool to determine which students belong in tier 3. It is only one tool, along with other information, for determining tier 2 status. After progress monitoring in tier 2, identify the students who do not respond to the tier 2 intervention well enough, and consider moving them into tier 3 interventions. Rather than looking at percentiles after tier 2 intervention, consider examining growth data rather than percentiles.

There is no direct-to-tier-3 decision that belongs in RTI—that opposes the "try interventions and gauge responsiveness" philosophy that is the essence of RTI. However, the role of MAP Growth is as a growth measure as well as a screener, so decisions about moving a student from tier 2 to tier 3 could certainly be informed by low growth in the tier 2 intervention, as measured by MAP Growth over time. Again, this would not involve looking at percentile scores; it would be about whatever growth criteria a school or teacher is using.

What criteria should I use to assign students to intervention?

The RTI Action Network website, which discusses RTI in detail, does not give any particular cut-points for tiered intervention, as a successful RTI program must be tailored to the individual needs of the school and its students. Their website contains a thorough section on how to implement an RTI program at your school, and what factors to consider. See RTI Strategies & Planning Tools at their website.

However, it seems common to assume approximately 80-90% of students will be in the tier 1 program at any given time, 5-10% will need tier 2 interventions, and 1-5% will not respond to tier 2 interventions and will need tier 3. This linked graphic showing the tiered RTI approach is linked to in a discussion hosted by the RTI Action Network and uses these percentages as well. These percentages roughly correlate with percentiles that are 1 and 2 standard deviations below the mean. With this in mind, you might use these percentiles as a starting point when you begin designing your RTI program.

However, you should always tailor these to match your school's individual needs. For example, a very high performing school might have far fewer than 15% of students with achievement levels that are 1 SD below the national means. In that case, they might adjust that threshold to a value that qualifies 15-16% of their students, which could be, say .5 of a SD below the mean. On the other hand, a below average school might have far more than 15% of students showing achievement scores that are 1 SD below the national means. In those cases, they might have to adjust the threshold to an even lower value (e.g., 2 SDs below the national mean) in order to identify 15-16% of their students.